ABCB1 and refractory malignant neoplasm: In taxane-resistant cancer, ABCB1 (encoding multidrug resistance protein 1; MDR1 or P-glycoprotein) and ABCG2 (encoding breast cancer resistance protein; BCRP) ABC transporters have been studied well as transporters of paclitaxel in several carcinomas [7,8,10].